Andrea Rivera ‘22

On September 20th, 2017, Hurricane Maria landed in Puerto Rico as a powerful Category 4 storm, the strongest to make landfall in 85 years. It caused approximately $90 billion in damages, making it the third costliest tropical cyclone in the US since 1900, more so than Hurricane Sandy and Irma (1). However, just a few weeks after the hurricane ravaged the island, a battle for the truth began regarding the number of people who died as a result of the storm. Calculating the death toll after the hurricane has been an arduous task for the government because of an inefficient system for accounting deaths. However, doing so is critical to the recovery of public health services in the country. Considering that Puerto Rico’s low-coastal regions and strategic position in the Caribbean are extremely susceptible to hurricanes, accurately estimating the amount of deaths in Puerto Rico after Hurricane Maria is vital to reducing the risk of injury, illness or death in the case of another natural disaster.

The official death count in Puerto Rico was 64 for almost a year. However, a study published in May 29, 2018 in the New England Journal of Medicine estimated that the mortality rate in Puerto Rico may have risen, with 4,645 excess deaths in the period following Hurricane Maria, compared to that same period of time in 2016 (2). This study, led by a collaboration between the Harvard T.H. Chan School of Public Health, the University of Colorado School of Medicine, and Carlos Albizu University in Puerto Rico suggests that Puerto Rico’s official death registry has severely underestimated the death toll. In order to understand the disjunction between 64 and 4,645 deaths, both the methods used in the survey and the government’s official death toll count must be evaluated.

According to the Centers for Disease Control and Prevention (CDC), deaths can be directly attributed to a tropical cyclone if they are caused by forces related to the event, better known as direct deaths, or if they are caused by unsafe or unhealthy conditions resulting in injury, illness, or loss of necessary medical services, known as indirect deaths arising from the hurricane (3). The government of Puerto Rico states that every death related to the hurricane must be confirmed by the Institute of Forensic Science. This poses a significant barrier to accurate reporting because not all bodies were accessible by medical examiners after the hurricane (4). Therefore, if the body was located in a remote location and there was no way for a medical examiner to confirm the death, it was not added to the official death count. This caused the death toll to account for deaths primarily directly related to the hurricane, but did not accurately portray the many victims who died indirectly because of the lack of electricity, medical care, and communication as a consequence of the storm. For example, a FEMA update from September 26, 2017, stated that 58 of the island’s 69 hospitals did not have power and fuel (5). Without these basic necessities, hospitals could not grant proper service and treatments because they could not refrigerate medications, support patients on dialysis, and perform surgeries.

The government was aware of the challenges in calculating indirect deaths, especially those stemming from lack of infrastructure and a severed health system. They recognized that the problem was beyond their scope, and in January 2018, the governor announced that an external task force had been appointed to examine all health-related deaths (6). This task force, led by researchers at the George Washington University Wilken Institute of Public Health, estimated that there were 2,975 excess deaths in Puerto Rico due to Hurricane Maria between September 2017 and February 2018 (7). These excess deaths were calculated by analyzing past mortality patterns from population census data from 2010 to 2017 and comparing them to the observed mortality for the period after Hurricane Maria. It was in June 2018, eight months after the hurricane, that the official government death toll was finally raised from 64 to 2,975 deaths.

In a similar manner, the Kishore et al. study conducted a community-based survey of a representative stratified random sample of 3,299 households, out of an estimated 1,135,507 total households, across Puerto Rico in early 2018 (2). The survey collected data relating to age, sex, cause of death if after the hurricane, hurricane-related migration, neighborhood deaths, and access to electricity, water, and cellular network coverage on an ordinal scale for each month during and after the hurricane (2). To calculate the excess deaths, the study estimated the mortality rate after the hurricane (from September 20 through December 31, 2017) and compared it with the official mortality rate for the same period in 2016 (2). The survey results showed an estimated mortality rate of 14.3 deaths per 1000 persons from September 20 through December 31, 2017. This rate would yield a total of 4,645 excess deaths during this period, equivalent to a 62% increase in the mortality rate as compared with the same period in 2016 (2).

The study also provided valuable information related to public health on the island and how it can be improved. For example, the survey found that interruption of medical care was the primary cause of sustained high mortality rates in the months after the hurricane. Thirty-one percent of households reported remoteness as the most frequent cause of disruption of medical services. For example, the rural community of Lares is 104 km away from Centro Medico of Puerto Rico, the first and most important medical facility on the island where most major surgeries are performed. Patients with terminal or critical illness in this area would have to travel over an hour to received medical treatment (8). Meanwhile, around 10% of households also reported inability to access medications, the need for respiratory equipment, inability to reach 911 services by telephone, and problems with closed medical facilities after the hurricane, amongst others. These problems illuminate a widespread lack of access to public health services on the island. There is a clear need for the Puerto Rican government, as well as communities, to develop effective contingency plans during and after disasters, such as training medical staff to enact a catastrophic events plan and performing hurricane drills.

When comparing these death tolls, it is important to emphasize the potential limitations of survey-based studies. The major source of error in the method used by the government is the poor access of medical examiners to remote and hurricane-ravaged areas in the island, whereas the major sources of error of a survey-based study are the inherent limitations of utilizing participants, including bias and errors. Some people might have misrepresented their conditions or incorrectly recalled their experiences, considering that the survey was conducted months after the natural disaster. The authors addressed this limitation by explaining that to address bias and errors in participant-reported data, the questions were kept simple, and the recall periods short.

The fact that the government could not come to a clear consensus about the death toll following Hurricane Maria demonstrates the need for appropriate and standardized methods to estimate both direct and indirect deaths. It is speculated that the real death toll of Puerto Rico following Hurricane Maria may never be known, even though it could have been possible for agencies in Puerto Rico to recover accurate statistics regarding the devastation of the hurricane. This demonstrates a lack of an organized infrastructure to properly address natural disasters and the need to implement emergency protocols to aid the population, especially those that may need emergency health services. These protocols should not only be established on a governmental or municipal level, but they should also be established between patients and doctors in order for them to become more tailored to the particular needs of every patient. Regardless of the exact death toll of the hurricane, the researchers’ attempts to estimate mortality rates have illuminated ways in which Puerto Rico could establish better emergency health services and data collection methods, both of which will help reduce the risk of injury and death in subsequent natural disasters.


(1)   Miami National Weather Service. (2018). Costliest U.S. tropical cyclones tables updated.

(2) Kishore, M.P.H., Marques, Ph.D., Mahmud, Ph.D, et al. (July 12, 2018). Mortality in Puerto Rico after hurricane Maria. N Engl J Med 2018; 379:162-170

(3) Atlanta: Centers for Disease Control and Prevention. (2017) A reference guide for certification of deaths in the event of a natural, human-induced, or chemical radiological disaster.

(4) Government of Puerto Rico. (2007). Ley del Departamento de Seguridad Pública de Puerto Rico.

(5) FEMA Daily Operations Briefing Tuesday September 26, 2017 8:30am EDT

(6) Lilley S. (January 4, 2018). Puerto Rico governor announces task force to examine hurricane-related deaths. NBC News.

(7) Milken Institute School of Public Health George Washington University.(2018). Ascertainment of the Estimated Excess Mortality from Hurricane Maria in Puerto Rico.

(8) Administración de Servicios Médicos de Puerto Rico. Historia del Centro Médico de Puerto Rico.





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